监听

If we can know their frequency we will monitor their talking.

如果我知道频率, 我就能监听谈话。

We have been monitoring the enemy's radio broadcasts to try to find out their secret plans.

"我一直在监听敌方电台广播,设法秘密计划。"

This instrument monitors the patient's heartbeats.

这台仪器监听病人心跳。